Project description:Enhancer of zeste homolog 2 (EZH2) is highly expressed in small-cell lung cancer (SCLC). Epigenetic modifications through EZH2 induce epithelial-mesenchymal transition (EMT). MicroRNAs (miRNAs) are small non-coding RNAs that modulate EMT to determine tumor phenotypes. miRNA expression profiles were compared between EZH2 siRNA-transfected SCLC cells and negative control-transfected SCLC cells, using miRNA array analysis. We identified miR-4448 as a target miRNA of EZH2 showing significant expressional differences in EZH2-knockdown cells.
Project description:Small cell lung cancer is the most aggressive type of lung cancer and has a high degree of plasticity, characterized by a remarkable response to chemotherapy followed by development of resistance. We show that intratumoral heterogeneity of SCLC is progressively established, indicated by the appearance of YAP+ and HES1+ SCLC tumor cells. Notch signaling is required for the generation of Non-NE SCLC cells, but not for the tumorigenesis of SCLC. Furthermore, YAP signals through Notch-dependent and independent pathway to induce REST expression to promote the conversion of NE to Non-NE SCLC tumor cells. In addition, YAP activation enhances the chemoresistance in NE SCLC tumor cells by downregulating GSDME, while inactivation of YAP in Non-NE SCLC tumor cells switches cell death from apoptosis to pyroptosis. Our study will not only provide novel insights into the molecular basis of SCLC tumorigenesis, but also the potential drug targets for SCLC therapy
Project description:Small cell lung cancer is the most aggressive type of lung cancer and has a high degree of plasticity, characterized by a remarkable response to chemotherapy followed by development of resistance. We show that intratumoral heterogeneity of SCLC is progressively established, indicated by the appearance of YAP+ and HES1+ SCLC tumor cells. Notch signaling is required for the generation of Non-NE SCLC cells, but not for the tumorigenesis of SCLC. Furthermore, YAP signals through Notch-dependent and independent pathway to induce REST expression to promote the conversion of NE to Non-NE SCLC tumor cells. In addition, YAP activation enhances the chemoresistance in NE SCLC tumor cells by downregulating GSDME, while inactivation of YAP in Non-NE SCLC tumor cells switches cell death from apoptosis to pyroptosis. Our study will not only provide novel insights into the molecular basis of SCLC tumorigenesis, but also the potential drug targets for SCLC therapy
Project description:Small cell lung carcinoma (SCLC) and large cell neuroendocrine carcinoma (LCNEC) are high-grade pulmonary neuroendocrine tumors. The neural basic helix-loop-helix (bHLH) transcription factors ASCL1 and NEUROD1 have been shown to play crucial roles in promoting the malignant behavior and survival of human SCLC cell lines. In this study, we find ASCL1 and NEUROD1 identify distinct neuroendocrine tumors, bind distinct genomic loci, and regulate mostly distinct genes. ASCL1 and NEUROD1 are often bound in super-enhancers that are associated with highly expressed genes in their respective SCLC cell lines suggesting different cell lineage of origin for these tumors. ASCL1 targets oncogenic genes such as MYCL1, RET, and NFIB, while NEUROD1 targets the oncogenic gene MYC. Although ASCL1 and NEUROD1 regulate different genes, many of these gene targets commonly contribute to neuroendocrine and cell migration function. ASCL1 in particular also regulates genes in the NOTCH pathway and genes important in cell-cycle dynamics. Finally, we demonstrate ASCL1 but not NEUROD1 is required for SCLC and LCNEC tumor formation in current in vivo genetic mouse models of pulmonary neuroendocrine tumors RNA-seq analysis performed on two ASCL1high and two NEUROD1high human SCLC cell lines to identify gene expression patterns in these cells. Also, we performed RNA-seq in mouse neuroendocrine lung tumors obtained from Trp53;Rb1;Rbl2 triple knockout model mice treated with Adeno-CMVCRE intratracheally.
Project description:The addition of immune checkpoint blockade (ICB) to platinum/etoposide chemotherapy changed the standard of care for small cell lung cancer (SCLC) treatment. However, ICB addition only modestly improved clinical outcomes, likely reflecting the high prevalence of an immunologically “cold” tumor microenvironment in SCLC, despite high mutational burden. Nevertheless, some patients clearly benefit from ICB and recent reports have associated clinical responses to ICB in SCLC with A) decreased neuroendocrine characteristics and B) activation of NOTCH signaling. We previously showed that inhibition of the LSD1 demethylase activates NOTCH and suppresses neuroendocrine features of SCLC, leading us to investigate whether LSD1 inhibition would enhance the response to PD1 inhibition in SCLC.
Project description:ASCL1 is a neuroendocrine-lineage-specific oncogenic driver of small cell lung cancer (SCLC), highly expressed in a significant fraction of tumors. However, ~25% of human SCLC are ASCL1-low and associated with low-neuroendocrine fate and high MYC expression. Using genetically-engineered mouse models (GEMMs), we show that alterations in Rb1/Trp53/Myc in the mouse lung induce an ASCL1+ state of SCLC in multiple cell types. Genetic depletion of ASCL1 in MYC-driven SCLC dramatically inhibits tumor initiation, but surprisingly converts tumors to a SOX9+mesenchymal/neural-crest-stem-like state that has the capacity to differentiate into RUNX2+bone tumors. ASCL1 represses SOX9 expression, as well as WNT and NOTCH developmental pathways, consistent with human gene expression data. SCLC demonstrates remarkable cell fate plasticity with ASCL1 repressing the emergence of non-endodermal stem-like fates that have the capacity for bone differentiation. Here we perform bulk RNA sequencing on RPMA tumor samples to compare gene expression patterrns with RPM tumors with intact ASCL1.
Project description:Small cell lung carcinoma (SCLC) and large cell neuroendocrine carcinoma (LCNEC) are high-grade pulmonary neuroendocrine tumors. The neural basic helix-loop-helix (bHLH) transcription factors ASCL1 and NEUROD1 have been shown to play crucial roles in promoting the malignant behavior and survival of human SCLC cell lines. In this study, we find ASCL1 and NEUROD1 identify distinct neuroendocrine tumors, bind distinct genomic loci, and regulate mostly distinct genes. ASCL1 and NEUROD1 are often bound in super-enhancers that are associated with highly expressed genes in their respective SCLC cell lines suggesting different cell lineage of origin for these tumors. ASCL1 targets oncogenic genes such as MYCL1, RET, and NFIB, while NEUROD1 targets the oncogenic gene MYC. Although ASCL1 and NEUROD1 regulate different genes, many of these gene targets commonly contribute to neuroendocrine and cell migration function. ASCL1 in particular also regulates genes in the NOTCH pathway and genes important in cell-cycle dynamics. Finally, we demonstrate ASCL1 but not NEUROD1 is required for SCLC and LCNEC tumor formation in current in vivo genetic mouse models of pulmonary neuroendocrine tumors ChIP-seq analysis performed on three ASCL1high and two NEUROD1high human SCLC cell lines to identify ASCL1 and/or NEUROD1 binding sites in these two types of cells. Also, we performed ChIP-seq for Ascl1 binding sites in mouse neuroendocrine lung tumors obtained from Trp53;Rb1;Rbl2 triple knockout model mice treated with Adeno-CMVCRE intratracheally.
Project description:Small cell lung cancer (SCLC) tumors harbor two subsets of cells that are defined by low (or undetectable) or high expression of Hes1, which is a common downstream target of the Notch signaling pathway. To better understand the role of the Notch pathway in SCLC tumor heterogeneity, we first isolated cells from these two populations using a GFP-reporter allele for Hes1 expression. We then used microarrays to identify the gene expression differences between these two groups.
Project description:Small cell lung cancer (SCLC) is a high-grade neuroendocrine tumor with a dismal prognosis and limited treatment options. Lurbinectedin, approved as a second-line treatment for metastatic SCLC, showed only a partial response in clinical trials highlighting the need to develop improved mechanistic insight and predictive biomarkers of response. In this study, we determine the preclinical efficacy of lurbinectedin in a comprehensive panel of SCLC cell lines and patient-derived xenografts of SCLC. Furthermore, we demonstrate that lurbinectedin, either as a single agent or in combination with osimertinib, causes remarkable anti-tumor response in multiple models of SCLC transformation. Transcriptomic analysis identified induction of apoptosis, repression EMT and modulation of PI3K/AKT, NOTCH signalling pathway being associated with lurbinectedin response in de novo and transformed SCLC models. We provide a mechanistic insight of lurbinectedin response in SCLC and is the first demonstration that lurbinectedin is a potential therapeutic target after SCLC transformation.
Project description:Small Cell Lung Cancer (SCLC) is the most aggressive type of lung cancer with early metastatic dissemination and invariable development of resistant disease for which no effective treatment is available to date. Mouse models of SCLC based on inactivation of Rb1 and Trp53 developed earlier showed frequent amplifications of two transcription factor genes: Nfib and Mycl. Overexpression of Nfib but not Mycl in SCLC mouse results in an enhanced and altered metastatic profile, and appears to be associated with genomic instability. NFIB promotes tumor heterogeneity with the concomitant expansive growth of poorly differentiated, highly proliferative, and invasive tumor cell populations. Consistent with the mouse data, NFIB expression in high-grade human neuroendocrine carcinomas correlates with advanced stage III/IV disease warranting its further assessment as a potentially valuable progression marker in a clinical setting. Genomic DNA from mouse small cell lung tumor samples was analyzed by mate pair sequencing and low coverage sequencing. And RNA from Nfib overexpressing mouse small cell lung cancer cell lines was further analyzed for high quality RNA profiles using Illumina Hiseq2500. This series contains only RNA-seq data.